Billionaire hedge funder Ken Griffin may be going through a messy divorce, but he is said to be buying a lavish apartment for himself at ultra-exclusive 220 Central Park South, dubbed “the billionaire’s bunker” by real estate insiders.

Chicago-based Citadel founder Griffin, who is worth $7 billion, is mired in an ugly divorce from his wife of 11 years, Anne Dias-Griffin, who is asking for $1 million per month in child support.

While they battle over their homes in Chicago, Aspen, Colo., and Manhattan’s 820 Fifth Ave., Griffin is rumored to be buying a condo at 220 Central Park South, the Robert A.M. Stern-designed, 950-foot-tall tower now under construction, where prices run from $30 million to $160 million-plus.

Although the skyscraper on “Billionaires’ Row” will not be completed for another two years, a third of the condos, representing a commitment of $1.1 billion from buyers, were reportedly already under contract by May.

But Griffin can clearly afford it. Paperwork filed in the divorce this spring revealed his monthly gross income “approaches $100 million,” and his net monthly income after taxes “averages more than $68.5 million” — which works out to more than $2.2 million a day.

Ken Griffin and Anne Dias-Griffin in 2007PatrickMcMullan.com

While sources insist his salary is calculated on the overall performance of the fund, not by the day, Griffin’s $25 billion Citadel hedge fund underlined its success by hiring former Fed Chairman Ben Bernanke as an outside adviser earlier this year.

When contacted about the apartment at 220 Central Park South, a spokeswoman for Griffin declined to comment Wednesday night. But a real estate insider said, “Ken has long been looking for a Manhattan trophy apartment. He wanted a $65 million home at 15 Central Park West three years ago, but his wife didn’t like it. Now he can make his own choices. The sale won’t close for two years, when, hopefully, his divorce, as nasty as it is, will have settled.”